222 METHODS FOR THE ANALYSIS OF GASTRIC JUICE
made in the same manner as this one, that is introduced at 88° C. The tubes thus prepared should be again checked up with the standard to see that no mistake has been made.
(2) Rose's Modification1 of the Jacoby-Solms Method.2— Dissolve 0.25 gm. of the globulin of the ordinary garden pea,3 Pisum satwum, in 100 c.c. of 10 per cent sodium chloride solution, warming slightly if necessary.4 Filter and introduce 1 c.c. of the clear filtrate into each of a series of six 5 test-tubes about 1 cm. in diameter. Introduce into each tube 1 c.c. of 0.6 per cent hydrochloric acid and permit a period of about five minutes to elapse for the development of the turbidity. Make a known volume of the gastric juice (5 to 10 c.c. is sufficient) exactly neutral to litmus paper with dilute alkali; and record the volume of the alkali so used. If acid metaprotein precipitates, filter it off; if there is no precipitate proceed without filtration. Dilute the clear neutral solution with a known quantity of distilled water (usually 5 volumes) making proper allowance for the volume of alkali used in the neutralization. Boil 5 to 10 c.c. of the diluted juice, filter and add the following decreasing volumes (c.c.) to the
iRose: Arch. Int. Med., 1910, 5, 459.
2Solms: Z. f. klin. Med., 1907, 64, 159.
3The globulin may be prepared as follows: "The finely ground peas, freed as much, as possible from the outer coating, are repeatedly extracted with large quantities of 10 per cent sodium chloride solution, the extracts combined, strained through tine bolting-cloth, and allowed to stand over night in large cylinders to deposit insoluble matter. The supernatant fluid is siphoned off and saturated with ammonium sulphate. The precipitate of albumin and globulin is filtered off, suspended in a little water, and dialyzed in running water for three days, until the salt has been removed, and the albumins have been dissolved. The globulins are filtered off and washed two or three times to remove the last trace of albumins. To purify further, the precipitate is extracted with 10 per cent sodium chloride solution, and filtered until perfectly clear. The resulting solution is neutralized to litmus paper by the cautious addition of dilute sodium hydroxide, and again dialyzed in running water for three days to remove the salts completely. The precipitated globulins are then filtered off and dried on a water-bath at 40° C. During the entire process of separation the proteins should be preserved with a mixture of alcoholic thymol and toluol/' This dried globulin is used in the clinical procedure.
4 This solution may be preserved at least two months under toluene.
6 A longer series of tubes may be used if desired. However, experience has shown that a series of six ordinarily affords sufficient range for all diagnostic purposes.